1. Field of the Invention
The present invention relates to a vehicular brake apparatus. More particularly, the invention deals with a knuckle for a brake assembly for rear drive vehicles. Still more specifically, the present invention offers a novel rear knuckle structure with brake features.
2. Description of Related Art
The brakes are one of the most important parts of an automobile as far as its safe operation is concerned. Depicted in FIG. 1 is a view of a car with its rear left wheel taken off to show the area touched upon by the present invention, whereas FIG. 2 illustrates two types of brakes currently employed on cars: disc brakes and drum brakes. A conventional drum brake circuit comprises a hydraulic system, brake shoes, and a brake drum. The hydraulic system is actuated by a driver pressing upon a brake pedal. The driver's action forces the hydraulic fluid out of the master cylinder and into each wheel brake cylinder. The fluid entering the wheel cylinders forces the opposed pistons farther apart, thus moving the brake shoes outward against the brake drum.
A typical prior art structure of caliper disc brakes assumes the presence of a revolving wheel disc operatively connected to a drive axle. An axle housing encloses the drive axle. Secured to the drive axle housing is a brake caliper whose function is to transmit braking forces from brake pads to the housing. The caliper is comprised of a casting accommodating at least one brake cylinder in which a piston adapted for a reciprocal movement is mounted. The cylinder and piston cooperate to define a pressure chamber which is pressurized by hydraulic fluid when the brake is actuated. A brake pad (or lining) assembly is mounted on the caliper and is moved toward the revolving wheel disc when the piston is moved outwardly in the cylinder due to brake pressure in the chamber. In so doing, the piston and brake lining cooperatively exert a friction force on the disc.
It is not uncommon in vehicles having rear disc brakes to incorporate brake shoes 10 (FIG. 2) within an inner drum portion (not shown) of a wheel disc 12 to accomplish a parking brake function while a caliper 14 is used to grip a radial outward portion of the wheel disc 12 to perform normal braking. In conventional prior art designs of that kind usually referred to as disc & DiH (for Drum in Hat) brakes, a flange 16 is provided on (usually bolted to) an axle housing 18, carrying a caliper slide subassembly (not shown) for mounting the caliper 14 thereto. Also, the brake shoes 10 are typically fastened to a sheet metal face plate 20 serving as a backing plate which is also bolted to the flange 16. A pin 22 is attached to the plate 20. It serves as an abutment surface for the brake shoes 10 transferring any force exerted on the brake shoes directly to the plate 20. To transfer braking forces further to the flange 16, a substantially solid face plate 20 is required. It is desired to eliminate the caliper slide subassembly and to have the plate thinner and thus less expensive.